The invention is based on an electric switching device including a power switching component arranged in a completely insulated housing. In watertight electronic devices, it is known from the German design Patent Publication No. DE-CM No. 79 09 986 to guide the heat outward by means of cooling plates, the heat being generated in the power switching components arranged on the cooling plates. The plots are used simultaneously for fastening the switching device. In electrical devices having a fully insulated housing, it is known to guide the heat from power transistors and power resistors directly to a connector plug by means of a cooling plate or to construct the cooling plate and connection plug as a structural connector part, by means of which the heat is guided outward and conducted away by a connecting cable harness having good heat conduction and large surface. This solution has been proven particularly in regulator switches and blinker units in the engine space of motor vehicles. Since such switching devices in motor vehicles have recently become more voluminous, while the connector plugs have become smaller, the connector plugs, which are combined to form connector plug units, have increases in number, and it is no longer possible to eliminate the heat generated at the power component of such switching devices solely by means of plugs which are assigned to them.